1. Field of the Invention
The present invention relates to hinge assemblies, and particularly to a hinge assembly for hinging a cover and a body of a foldable electronic device together.
2. Prior Art
Portable electronic devices, such as cellular phones and PDAs (personal digital assistants), are becoming ever more popular with the development of wireless communication technology and data processing technology.
For example, a foldable cellular phone commonly has a cover and a body joined by some type of hinge that allows the cover to fold upon the body. Some foldable phones have most of the electronics provided in the body. The cover normally contains fewer electronic components than the body. Other foldable phones have essentially all the electronics provided in the body, with the cover serving only to cover and protect the keypad and the display of the phone.
U.S. Pat. No. 5,628,089, issued to Wilcox et al. and entitled “Radiotelephone Having a Self Contained Hinge,” discloses a hinge for use in a miniaturized radiotelephone. This hinge is represented in FIG. 5. The hinge 80 comprises a spring 82, a cam 83 and a follower 84 assembled into a cylindrically hollow can 81 via an open end thereof, and held in assemblage by a cap 85 coupled to the can 81 over the open end. The hinge 80 can be attached in a cavity of a cover and a cavity of a body of the radiotelephone.
This kind of self contained hinge is desired by many foldable cellular phone manufacturers because it can be purchased as a separate unit, thereby eliminating the steps associated with assembling such hinge during manufacturing. However, a foldable cellular phone with such hinge can be opened automatically only after the cover has first been turned about the body by a user. It is not easy for the user to open the cellular phone with only one hand, for example when the user is driving a car or is otherwise occupied. Furthermore, the cover is prone to open quickly and jar against the body. After repeated use, the body and the cover are liable become worn out and not operate properly.
Thus, a need exists for a convenient and highly reliable hinge assembly which is suitable for use in a foldable electronic device, and which overcomes the above-described problems.